1. Field of Disclosure
This invention relates in general to systems for controlling the distribution of fluid to one or more wellbores, and in particular to pressure relief systems for manifolds associated with hydrocarbon production systems.
2. Description of Related Art
Certain hydrocarbon production related activities, such as well stimulation and hydraulic fracturing, require the pumping of pressurized fluid down hole. During hydraulic fracturing, as an example, a fluid is pumped into a subterranean geologic formation through the wellbore. The fluid is provided at a sufficient pressure to fracture the geologic formation, thus facilitating the recovery of hydrocarbons from the formation. Fluid is pressurized by one or more pumps, which is then pumped down high pressure flow lines to the well bore.
During the hydraulic fracturing process, the pumps operate at a predetermined pressure, and push the fluid down hole. Pressure spikes are a common phenomenon in hydraulic fracturing. For example, during a screen out, the solids carried in a treatment fluid, such as proppant in a fracture fluid, create a bridge across a restricted flow area. The bridge partially or fully blocks the flow of treatment fluid and creates a sudden and significant restriction to fluid flow that causes a rapid rise in pump pressure. In other cases pressure spikes can be attributed to machine faults or human errors such as improper setting of the pumps.
If the pressure spike is not sensed, then the components of the fluid flow system are exposed to a significant pressure, and equipment that is rated below the pressure spike can be damaged. The components of the distribution manifold and other pressure equipment is designed to operate at a rated design pressure with industry standard safety factors. When fluid pressure exceeds the design pressure, equipment associated with the fluid distribution system at the distribution manifold, down hole, or otherwise, can become damaged. In addition, when the design pressure is exceeded, a destructive blowout can occur. This blowout can result in the ejection of components or high pressure fluids, leakage of fluids to the environment, or both.
In some current hydraulic fracturing systems, operational personnel observe pressure readings at a surface location and make a decision on when to shut down the hydraulic fracturing system. In other current hydraulic fracturing systems, the pumping truck will have a pressure relief system. However the pressures at the truck can be so high that if such a relief system is utilized to relieve pressure, the magnitude of the pressure spike could have already damaged the hydraulic fracturing system equipment, or other associated system components.